WASHINGTON--Pope Francis launched his first visit to the United States with a characteristic gesture of humility on Tuesday, and sent a conciliatory message to the world's wealthiest nation about his frequent criticism of capitalism. After a red carpet welcome by President Barack Obama at an air base near the capital, the 78-year-old Argentine headed off to Washington not in a limousine as is customary but in a modest Fiat. Schoolchildren cheered the pontiff as his Alitalia plane landed, chanting "We love Francis, yes we do. We love Francis, how about you?" Obama, his family and Vice President Joe Biden greeted the pope in an honour given to few foreign dignitaries. The pope's motorcade ride in the black Fiat 500L was in sharp contrast to the way that U.S. presidents and visiting world leaders sweep into town in limousines and large SUVs after arriving at Joint Base Andrews air base. The six-day visit to America gives Francis a chance to showcase some of his favourite themes like compassion and simplicity in the world's most powerful country. The pontiff has often taken aim at capitalism, but on the plane bringing him from Cuba he said it would be wrong to presume that his concerns about economic injustice make him a leftist. "Maybe an explanation was given that led to the impression that I am a bit to the left but it would be an error of explanation," Francis told reporters. The first Latin American pope has electrified liberal-leaning U.S. Catholics, Democrats and many non-Catholics with a shift in emphasis toward concern for the poor and immigrants and his appeals for action against climate change. But his criticism of unbridled capitalism has unsettled U.S. conservatives. The leader of the world's 1.2 billion Roman Catholics, Francis said his teachings on economic fairness and climate change are "all in the social doctrine of the Church." "It is I who follow the Church," he said. Francis will give the first speech by any pope to the U.S. Congress on Thursday, an address to the U.N. General Assembly in New York on Friday and an open-air Mass in Philadelphia where 1.5 million people are expected to attend. Francis ended a four-day Cuba trip and headed to the United States with a message of reconciliation for the former Cold War foes while avoiding controversy on the U.S. trade embargo or human rights on the Communist-run island. The pope told reporters he hopes the United States will lift its long trade embargo on the Communist-run island but does not plan to raise it in his address to Congress this week.